When Daryl Hall and John Oates begin a two-night stand at Hard Rock Live this Friday, they’ll experience something Oates believes eluded the R&B-loving pop duo at the height of their now-43-year-old career: respect.

“Back in the day, in the ’70s and ’80s, when we were having all these big No. 1 records, people just kind of wrote us off as this superficial hitmaking machine that wasn’t very substantial or wasn’t very deep,” Oates says by phone during a tour stop in Panama City. “But all that’s changed, because there’s a greater respect for making music that can stand the test of time. The very fact that we’re out here today, playing sold-out shows every night, is a testament to the fact that the music that we made has stood the test of time.”

For Oates, this newfound respect has come from bands whose members were either still in diapers or yet to be born when songs such as “She’s Gone,” “I Can’t Go for That (No Can Do)” and “Maneater” first appeared on the radio. Oates names Gym Class Heroes, Hot Chelle Rae and the Killers among those acts who cite Hall and Oates as an influence, thereby turning their fans on to the duo’s music. For further evidence of Hall and Oates’ late-arriving cachet, the credibility-obsessed can look to “Live From Daryl’s House,” a popular web series in which Hall jams with the likes of Sharon Jones, Minus the Bear and Grace Potter, and Oates’ upcoming appearance at the Bonnaroo music festival, where he’ll lead a “Soul Superjam” with My Morning Jacket’s Jim James, drummer Zigaboo Modeliste and the Preservation Hall Jazz Band.

Everyone else, Oates argues, can just listen to the music.

“Fortunately for us, all our hits sound great. I’m not saying it from an ego point of view. It’s the truth,” Oates says. “There’s a crazy reason that we’re selling out every show we play after 40 years to a whole new generation of audience. I mean, we have our old-school fans, who’ve been around for years and years, but at the same time, our audience is made up of a younger generation who have rediscovered us and are coming out to see us and just love the songs.”

As for his solo work, Oates is still heavily indebted to the soul giants who informed so much of the music he wrote with Hall. On his 2011 album, “Mississippi Mile,” and last year’s live followup, “The Bluesville Sessions,” he covers the Impressions’ “It’s All Right,” Percy Mayfield’s “Please Send Me Someone To Love” and the Coasters’ “Searchin’, ” among other classics. But on these performances, Oates reveals an affinity for vintage folk and country, letting his voice ramble around in its lower, grittier registers and trading down-home licks with Sam Bush, the veteran bluegrass fiddler and mandolinist, and Jerry Douglas, best known for playing Dobro with Alison Krauss and Union Station.

“That’s the thing that I did before I met Daryl. It goes way, way back. It goes back to my childhood,” he says. “When I met Daryl, I was playing folk music and folk-blues and bluegrass, in addition to playing urban R&B. I always make a joke that I have a split musical personality. And I do. I have this rootsy, Americana background that’s really a major part of my musical history. And I also have an urban R&B thing that I’ve done, as well. So, like, I can be wearing a sharkskin suit one night and a denim work shirt the next night and doing two different kinds of music, and they both feel very comfortable.

“It’s just a unique set of influences, I guess. So for me to be able to work with Sam and Jerry and people like that was a real thrill and a real honor,” Oates continues, “because I respect their musicianship so much. But at the same time, I don’t think I can hang with them as instrumentalists, because those guys are on a different level. But in terms of influences and things, I relate and understand exactly what they’re doing. It’s been great.”

Oates says working with Bush, Douglas and the Nashville-based musicians with whom he recorded “Mississippi Mile” has inspired him to delve deeper into his roots with a project he’s calling “Good Road To Follow.” Beginning March 12, he plans to release a new single every month for a year, and perhaps longer, featuring collaborations with artists such as Vince Gill, OneRepublic singer Ryan Tedder and Hot Chelle Rae. He recorded the first single, “Stand Strong,” with the banjo player Teddy Morgan and the singer Bekka Bramlett.

“Every song is different in its own way,” Oates says of the “Good Road To Follow” singles. “It goes back and allows me to touch on all these things that I like: folk music, blues, country, rock, whatever.”

One thing you may not see Oates returning to, however, is the mustache he wore throughout the ’70s and ’80s. Resembling a fat, furry, magnificent rodent, the mustache ranks among the iconic facial hair of that era, so much so that in 2009, Oates spoofed it in a pair of animated shorts for Will Ferrell’s Funny or Die website. Even though he shaved off the mustache more than 20 years ago, Oates has no trouble explaining its enduring fame.

“Because I had the best one, that’s why,” he says with a laugh. “I think it had to do with MTV, just getting that ridiculous, constant, ubiquitous exposure that was just everywhere all the time. And now, to this day, it still plays, and it’s on YouTube. It keeps coming back. The mustache thing was just such a big part of the ’70s, and even into the ’80s. When you look back at that period of time, everyone had a mustache. It was crazy. If you look around today, the beard is the new thing. The beard is the mustache of today. Everyone has facial hair. Hey, it’s a style.”